The present invention relates to a method and a system for securely delivering encrypted digital data.
Extraordinary headway in digital technology today has made it possible to deliver all kinds of digital data over networks or by means of storage media. Such data include character data (e.g., text, symbols and figures), audio data (voices and pieces of music), video data (still and moving pictures), audio-video composite data (movies and broadcast programs), program data, database data and others, typically referred to as content data, or simply content.
Some digital data delivered may consist of a single data file; others may be composed of a plurality of data files. Some of such data files may have information composed of a single content; others may include information constituted by multiple contents. Each of these contents may be divided into a plurality of digital data.
It is not difficult to make perfect copies of digital data. Once unauthorized copies are made (e.g., through unauthorized decoding and reproduction, unlawful duplication, or illicit diversion of products to the black market), copyright holders and others involved in the legitimate creation, display or delivery of content may suffer significant economic injury or other damage. Concern over such unauthorized practices has accelerated the recent move to establish a framework for protection of content providers (such as content producers, distributors and deliverers). In particular, the possibility of devising measures to deter unauthorized copies is being explored to protect valuable contents that take enormous cost and labor to produce (such as movies).
The present invention is intended to defeat unauthorized copying, reproduction, diversion, etc. of content; and provides a technique for delivering digital data in a secure manner that makes illicit copying difficult.